You can make a planter out of pretty much anything. An old metal file cabinet is just about the perfect size for a raised planter you can roll in and out of the sunlight as needed.

Remove the drawers, prime and coat with exterior nontoxic paint, and turn the cabinet on its back for a great deep planter for growing tomatoes and other deep-rooted plants. For more structural support, add some 2-by-4s to the bottom of the planter, which you can drill casters into.

You can find old metal filing cabinets at secondhand stores or just reuse an aging one you already own. The drawers can be transformed into planters as well, and, as the photo at left shows (courtesy of ARTS), you can apparently grow plants in a filing cabinet while still using the other drawers. Photo by Sasquatch Books